The Instructional Group Activities Design (IGAD) refers to activities which aim to improve professional development and learning skills, in which a learning-centered teaching process is adopted and students study in small groups. The study aimed to both introduce the IGAD and determine pre-service science teachers' opinions on IGAs that were performed during the practice hours of the course "Special Teaching Methods I." In line with this aim, opinions of 56 pre-service science teachers on the practices were received. An opinion form, which includes open and close-ended questions, was used as a data collection tool. According to the results of the study, pre-service science teachers stated that the practice mostly contributed to their professional and social development areas. Regarding the negative aspects of the practices, pre-service science teachers underlined that they had difficulty regarding time and experienced certain group problems. Based on these findings, positive and negative aspects of the instructional group activities design for teacher training were discussed, and some recommendations were presented.